1. Field of the Invention
The present invention relates generally to automobile exhaust sound and emission control, including a catalytic exhaust converter and a resonator installed within the exhaust system for the reduction of exhaust noise, and to an exhaust sound attenuation and control system having multiple flow paths for reducing exhaust noise.
2. Description of the Related Art
By the time of the 1950s, it was becoming apparent that the ever-increasing volume of automobile and truck traffic was generating exhaust emissions which were adversely affecting the environment. This was particularly true in urban areas and other areas where geographic and meteorological conditions combined to create areas where such emissions do not readily dissipate. Accordingly, by the late 1960s, various regulations were being implemented to require equipment to reduce exhaust emissions output from automobiles, particularly in California and other urban areas.
While early emissions control efforts provided some relief, standards have become increasingly strict in order to keep pace with the ever-increasing volume of automobile and truck traffic throughout the U.S.A. With the development of the catalytic converter, which uses one or more noble metals such as platinum, rhodium, and/or palladium to produce an oxidizing and/or reducing catalytic reaction with the exhaust products and heat generated by the exhaust, a real breakthrough was achieved in the control of vehicle emissions. An automobile equipped with one or more catalytic converters was capable of meeting most, if not all, of the exhaust emissions standards of the time, and the use of catalytic converters became commonplace on automobiles and light trucks powered by spark ignition engines in the U.S.A.
However, long before the recognition of chemical or particulate automobile exhaust emissions as a hazard, another type of automobile exhaust emission had been recognized, i.e., noise or sound. In fact, legislation in virtually every area of the world requires motor vehicles to have equipment which reduces this other emission. Accordingly, mufflers, resonators and other such sound attenuating devices have been known for many years, since shortly after the very earliest development of the internal combustion engine. These two types of emissions control devices, i.e., catalytic converters and mufflers or other sound attenuating devices, have generally not been combined into a single unit due to conflicting characteristics and physical requirements.
In the case of exhaust silencing devices, the maximum desired temperatures for such devices in operation are generally relatively low in comparison to the temperatures achieved in catalytic converters. Mufflers, resonators, and such sound attenuating devices are generally constructed of mild steel, perhaps with an aluminized exterior coating. Very high temperatures cause the aluminized coating to be burned off, and cause both the interior and (after removal of any coating) exterior to be oxidized, to the point of burn-through or rust-through, in relatively short order. While mufflers and other related devices have been constructed of stainless steel in order to reduce oxidation problems, these devices are relatively costly due to the material used and the difficulty in working with such material, in comparison to mild steel. Many, if not most, automobile owners would rather replace a standard steel exhaust system once or twice during their ownership of the car, rather than pay for a replacement system which costs perhaps three times that of a standard, mild steel system.
On the other hand, catalytic converters require relatively high temperatures for efficient operation. If a catalytic converter does not reach a minimum temperature, the catalytic reactions therein will be greatly reduced. Thus, most catalytic converters are constructed of relatively costly materials in order to withstand the heat generated therein. Even so, most converters are installed at some distance from the engine in order to preclude being subjected to excessive heat which could damage them.
While mufflers are generally installed toward the extreme downstream end of the exhaust system, many exhaust systems also incorporate a resonator. Resonators are also sound attenuation devices, but operate on a completely different principle than that of the muffler. The muffler is adapted to cancel most sounds therein by reflecting the sounds (and the exhaust) back and forth through a series of parallel pipes therein, and by forcing the exhaust gases laterally outwardly through relatively small passages in the pipes. The resonator is adapted to pass the exhaust gases therethrough with little or no impedance, while canceling or absorbing sounds within a certain relatively well defined frequency range. This range is generally relatively high, with the muffler being relied upon for the attenuation of lower exhaust frequencies.
As the resonator is adapted to attenuate different frequencies than the muffler, and operates on a different principle, it is generally placed elsewhere in the exhaust system, somewhat forwardly of the muffler, although the resonator may be placed either upstream or downstream of the muffler. The catalytic converter is typically installed forward of the muffler in an automobile, in order to avoid excessive exhaust heat while still accepting sufficient exhaust heat to function. While resonators do not generate internal heat due to chemically reacting the exhaust products, as do catalytic converters, they still must be structured to accept a relatively high exhaust temperature due to their location relatively near the engine. However, heretofore no combining of a catalytic converter and a resonator has been accomplished, to the knowledge of the present inventor.
Accordingly, a need will be seen for a catalytic converter and resonator combination which serves both purposes in a single device. The device may be installed in a conventional automobile exhaust system, between the engine and a conventional muffler and/or tailpipe. Different embodiments may be provided for single and dual exhaust systems, each of which may include one or more catalytic converter elements or “bricks.” When used with a pre-catalytic converter, a muffler for further sound attenuation may not be required, depending upon the particular automobile, engine, and exhaust system.
It is also noted that mufflers and resonators have generally not been combined into a single unit due to conflicting characteristics and physical requirements. In another aspect of the present invention, an exhaust sound attenuating device is presented which serves the function of both muffler and resonator in a single unit, and may also include means for treating exhaust emissions as well. While the present inventor has developed devices which combine the function of the catalytic converter and resonator in a single device, he knows of no single device which combines the functions of the muffler and resonator in a single unit, and which may also include at least some limited catalytic conversion function as well. Such a device would be desirable, as it would save space beneath the vehicle, would reduce weight, and would likely reduce exhaust backpressure in comparison to a series of separate devices.
In addition to the above catalytic converter and resonator combination, and resonator and muffler combination with additional catalytic conversion function, the present disclosure also describes a series of alternative embodiments generally comprising a resonator type device having a series of longitudinally disposed tubes of various diameters and lengths therein. At least a portion of the exhaust gases pass through the tubes, with another portion of the gases passing through a series of V-shaped baffles. The net effect is the canceling of exhaust noise across a relatively wide band of sound frequencies. The device may also incorporate one or more catalytic converter elements therewith, and/or may include a removable end or ends therewith for access to internal components. The removable end(s) may be incorporated with other devices disclosed herein, as well.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 3,061,416 issued on Oct. 30, 1962 to George P. Kazokas, titled “Catalytic Muffler,” describes a device having a series of vanes within the inlet end and a peripherally disposed catalytic material, with a portion of the device further having a backflow of ambient air drawn through the outer shell by entrainment from the exhaust within the device. Kazokas notes his concern regarding the emission of lead in various forms into the atmosphere, from the burning of fuel containing tetraethyl lead. It is also known that the combustion products of leaded fuels will contaminate the catalytic elements of a catalytic converter, rendering it ineffective in a very few miles of vehicle operation using such leaded fuels. The solution provided by Kazokas is to separate the relatively heavy lead particles from other gases by means of centrifugal reaction. He provides a series of centrifugal vanes near the inlet end of his device for this purpose. However, leaded fuels have been banned for many years, and there is no further need to provide any swirling or centrifugal action to the gases passing through such a device. Accordingly, the vanes within the present exhaust devices or systems do not impart any swirling or centrifugal action to the gases passing therethrough. Moreover, the entrainment of ambient air through the outer shell of the Kazokas device has the effect of lowering the internal temperature within the device, thereby lessening the efficiency of the peripherally disposed catalytic conversion material along the inner shell. In contrast, the present systems locate such catalytic conversion materials and elements generally along the center of the device, where maximum temperatures occur to maximize the catalytic conversion reaction.
U.S. Pat. No. 4,032,310 issued on Jun. 28, 1977 to Vincent E. Ignoffo, titled “Muffler And Exhaust Gas Purifier For Internal Combustion Engines,” describes a device having three joined components. The first component at the inlet end of the device comprises an empty expansion chamber, with no exhaust modifying componentry therein. The next chamber in line comprises a housing containing small particles of material for chemically treating the exhaust, i.e., carbon particles and/or noble elements for treating the gases catalytically. The outlet portion of the device includes a concentric sound absorbing material which surrounds an outlet pipe, with the volume of the pipe communicating with the sound absorbing material. The Ignoffo device is thus essentially a straight pipe having only a single pathway therethrough, with no convoluted pathway for the gases to follow. Such devices cannot serve as resonators, as they lack the multiple pathways required to cause different frequencies to occur, and to cancel those frequencies, thereby reducing the noise output of the system. While Ignoffo provides for access to the catalytic element of his device, he places this element in the center of the device, requiring both end components to be removed in order to repair or replace the central catalytic element. Moreover, Ignoffo uses a series of bolts installed through flanges, making the operation even more cumbersome. The present system utilizes a much more elegant mechanism for accessing the internal elements of the device.
U.S. Pat. No. 4,050,903 issued on Sep. 27, 1977 to Charles H. Bailey et al., titled “Combination Muffler And Catalytic Converter,” describes a device having a relatively convoluted exhaust gas flow path therethrough. The exhaust gases enter through a venturi, which is used to draw air into the exhaust to mix therewith. (It is noted that mufflers are inherently pressurized somewhat higher than ambient when in operation, due to the backpressure created in such devices, yet Bailey et al. do not utilize any other means than the venturi effect to introduce the air into the muffler.) The exhaust and air are mixed by a deflector cone extending into the outlet of the venturi. From this point, the exhaust mixture passes through a series of holes in a transverse plate, and thence through holes in another plate to enter the catalytic converter. The present catalytic converter and resonator combination is a straight through, axial flow, free flow configuration, adapted for the attenuation of specific frequencies, unlike the muffler configuration of Bailey et al. Also, the catalytic converter element of the present invention is located within the forward portion of the device, where it is subjected to the highest possible exhaust heat which occurs within the entire device. Bailey et al. locate their catalytic converter element in the rearward portion of the device, where the exhaust gases have cooled somewhat by their passage through the convoluted flow path of the forward muffler portion of the device. As the muffler itself is generally located to the rear of the exhaust system, some efficiency would be lost in the Bailey et al. device, due to the relatively cooler exhaust temperatures by the time the exhaust gases arrive at the catalytic converter element.
U.S. Pat. No. 4,364,761 issued on Dec. 21, 1982 to Morris Berg et al., titled “Ceramic Filters For Diesel Exhaust Particulates And Methods For Making,” describes a particulate trap for use with diesel engines. The Berg et al. device comprises a ceramic unit having a series of inlet and outlet passages therein. However, the inlet and outlet passages are not connected to one another. Rather, the ceramic material is porous, to allow gases to flow through the walls of the ceramic material from the inlet side to the outlet side. The porosity is configured to allow exhaust gases to flow, but to trap larger carbon particles typically generated during diesel engine operation. While Berg et al. describe their ceramic structure as having thin walls, this device cannot be used as a catalytic converter element, as the catalytic coatings would block the minute porosities between the inlet and outlet passages, thereby blocking gas flow through the device. In contrast, the present invention in its various embodiments utilizes conventional catalytic converter elements, and/or coats the sides of the internal passages with catalytic material to provide the desired reactions while also allowing exhaust gases to flow through the device.
U.S. Pat. No. 4,393,652 issued on Jul. 19, 1983 to John H. Munro, titled “Exhaust System For Internal Combustion Engines,” describes an exhaust device including an upstream muffler, a generally centrally located spark and moisture arrestor, and a downstream chamber having a replaceable catalytic element therein. The disadvantage of locating the catalytic element farther from the combustion source, where the element receives less heat from the exhaust and thus produces a less efficient reaction, has been noted further above. Moreover, Munro describes the use of a gas absorbent or adsorbent material, such as charcoal, in combination with his catalytic element. The use of an adsorbent material such as charcoal in a motor vehicle engine exhaust system is not understood, as the relatively large volume of exhaust gases passing through the system would result in the adsorption of only a miniscule quantity of impurities in the exhaust, in comparison to the total exhaust volume relative to the amount of charcoal in the system. The amount of charcoal required to absorb the vast majority of impurities from the exhaust of a motor vehicle engine, would be prohibitive.
U.S. Pat. No. 4,425,304 issued on Jan. 10, 1984 to Masayuki Kawata et al., titled “Catalytic Converter,” describes a device comprising a single shell or container with two converter units or “bricks” installed in series therein. No sound attenuating means is disclosed by Kawata et al. in their catalytic converter.
U.S. Pat. No. 4,426,844 issued on Jan. 24, 1984 to Keiichi Nakano, titled “Engine Muffler Of Heat-Exchanging Type,” describes a device incorporating a pair of catalytic converter components therein. The two catalytic converter components are positioned in front of the heat exchanger, which also acts as a muffler. Exhaust gas flow enters the device by means of a radial pipe, and flows radially to enter and exit the myriad of axial heat exchange passages in the muffler and heat exchanger element. In contrast, the present invention provides for strictly straight through, axial flow of exhaust gases therethrough, in order to reduce backpressure therein and provide the greatest possible free flow of the exhaust gases. The present device is not a muffler, with a convoluted and restrictive flow path, but rather is a resonator, adapted for the reduction or canceling of certain specific exhaust gas frequencies.
U.S. Pat. No. 4,541,240 issued on Sep. 17, 1985 to John H. Munro, titled “Exhaust System For Internal Combustion Engines,” is a divisional patent of the parent '652 U.S. Patent to the same inventor, discussed further above. The same points raised in the discussion of the Munro '652 Patent are seen to apply to the Munro '240 U.S. Patent as well.
U.S. Pat. No. 5,014,510 issued on May 14, 1991 to Franz Laimbock, titled “Exhaust System, Particularly For Two-Stroke Cycle Internal Combustion Engines,” describes an exhaust assembly having a relatively wider expansion area which includes a primary catalytic converter therein. A longitudinal divider is installed upstream of the primary catalytic converter element, with the divider also being coated with catalytically reactive material. It is well known that two stroke cycle exhaust systems are relatively limited in their configurations, as it is critical that the system be tuned so as to assist each exhaust pulse in its passage in order to draw the subsequent pulse or charge from the cylinder, in order to attain optimum efficiency and to preclude overheating of the engine. Accordingly, Laimbock does not provide any internal baffling within his exhaust system in order to attenuate noise levels, as is provided by the present exhaust system.
U.S. Pat. No. 5,016,438 issued on May 21, 1991 to Harold L. Harris, titled “Emission Control Apparatus,” describes a combination exhaust device having a pair of catalytic converter elements in tandem therein. Only a portion of the exhaust gases pass through the first element, with some of those gases being recirculated back through the first element. All of the exhaust gases pass through the second element. In contrast, all exhaust gases pass through all of the catalytic converter elements of the present invention, when plural elements are provided in tandem. In addition, Harris places his catalytic elements generally in the center of his exhaust device, where the heat is reduced in comparison to the entry end of the device. The loss of efficiency for catalytic converter elements operating at lower heat levels, has been noted further above.
U.S. Pat. No. 5,043,147 issued on Aug. 27, 1991 to Glen Knight, titled “Combined Muffler And Catalytic Converter Exhaust Unit,” describes a device with a pair of converters being installed within the first portion of the muffler shell. The exhaust gases are then forced to travel a sinusoidal, convoluted path forward and aft through the muffler portion, with gases being exchanged between various pipes within the muffler portion due to perforations provided through the pipes. The present straight through, free flow resonator provides greatly reduced backpressure, in comparison to a muffler configuration such as the Knight apparatus. The disadvantages of including catalytic converters within a muffler located toward the outlet end of the exhaust system, with its reduced heat, have been noted further above in the discussion of the patent to Bailey et al., and apply here as well.
U.S. Pat. No. 5,108,716 issued on Apr. 28, 1992 to Kimiyoshi Nishizawa, titled “Catalytic Converter,” describes a device having two converter components housed within a single container or shell. No sound attenuation means is disclosed by Nishizawa, as provided by the present catalytic converter and resonator combination.
U.S. Pat. No. 5,183,976 issued on Feb. 2, 1993 to R. J. Plemons, Jr., titled “Adjustable Sound Attenuating Device,” describes a resonator type device having essentially a straight through flow pattern. No double wall outer shell, additional sound insulating material, or catalytic elements are disclosed by Plemons, Jr. in his exhaust device.
U.S. Pat. No. 5,206,467 issued on Apr. 27, 1993 to Noboru Nagai et al., titled “Muffler With A Catalyst,” describes a relatively small, canister type muffler as used on small two and four stroke engines (e.g., lawnmowers, etc.). The Nagai et al. muffler essentially has four compartments, with a pipe-like first compartment projecting into a second compartment, which communicates with a third compartment which leads to a small fourth compartment with a relatively small exhaust outlet passage. The exhaust gases do not pass longitudinally through a series of elongate passages, as in the present system, and the configuration of the Nagai et al. device cannot provide any resonator effect.
U.S. Pat. No. 5,220,789 issued on Jun. 22, 1993 to James E. Riley et al., titled “Integral Unitary Manifold-Muffler-Catalyst Device,” describes an exhaust manifold and system which is bolted directly to the cylinder head of the engine. While Riley et al. include a conventional catalytic converter element, or “brick,” within their manifold, they fail to include any internal baffling to control the exhaust sound level within their manifold. The only internal passages within their device are formed by the relatively small, straight passages of the catalytic converter element itself, which Riley et al. prefer to be as nearly straight as possible to encourage laminar flow therethrough. In contrast, the present system provides a circuitous exhaust flow path therethrough, to attenuate noise levels optimally.
U.S. Pat. No. 5,248,859 issued on Sep. 28, 1993 to Alexander Borla, titled “Collector/Muffler/Catalytic Converter Exhaust Systems For Evacuating Internal Combustion Engine Cylinders,” describes various embodiments of an exhaust system in which a muffler jacket may be installed surrounding a collector unit. Borla also provides catalytic converter elements, but in each case the catalytic converter elements are installed as separate units within the individual exhaust header pipes adjacent the cylinder head of the engine, or in the individual header pipes immediately upstream of the collector. No internal resonator structure is provided by Borla, nor does he utilize a single catalytic converter element or multiple elements in tandem disposed within a single exhaust passage, as provided by the present exhaust system invention.
U.S. Pat. No. 5,265,420 issued on Nov. 30, 1993 to Erwin Rutschmann, titled “Exhaust System Of A Multi-Cylinder Reciprocating Engine,” describes a system in which a single catalytic converter is provided for each cylinder bank of a V-8 engine. Exhaust gases pass through the two catalytic converters, thence to a single transverse muffler. Thus, Rutschmann requires three separate housings or units for the two catalytic converters and single muffler of his system, whereas the present catalytic converter and resonator combination are combined within a single housing. Also, the Rutschmann system does not provide straight through flow, but requires the exhaust gases to make several turns between the catalytic converters and the transverse muffler inlet and outlet. No resonator is disclosed by Rutschmann.
U.S. Pat. No. 5,325,666 issued on Jul. 5, 1994 to Erwin Rutschmann, titled “Exhaust System Of An Internal-Combustion Engine,” describes a system somewhat similar to the apparatus of the '420 U.S. Patent to the same inventor, discussed immediately above. The convoluted routing of the exhaust gases, the use of separate housings or components for the catalytic converters and mufflers, the use of a plenum around the catalytic converters, and other differences, make the Rutschmann apparatus distinct from the present catalytic converter and resonator combination. Again, it must be noted that a muffler is not a resonator, and does not provide straight through flow of exhaust gases and the attenuation of a relatively narrow range of frequencies.
U.S. Pat. No. 5,355,973 issued on Oct. 18, 1994 to Wayne M. Wagner et al., titled “Muffler With Catalytic Converter Arrangement; And Method,” describes a muffler having a straight flow through pattern; no convoluted or sinusoidal flow pattern is provided in the Wagner et al. exhaust device. While Wagner et al. provide a concentric tubular element within their muffler, they do not provide a series of parallel tubular exhaust passages serving as a resonator, as in the present invention, nor do they provide a series of V-shaped baffles in combination with such tubular elements. Moreover, no double walled shell having additional acoustic insulation therein is disclosed by Wagner et al., which structure is a part of at least some embodiments of the present exhaust system invention.
U.S. Pat. No. 5,378,435 issued on Jan. 3, 1995 to Albino Gavoni, titled “Silencer Combined With Catalytic Converter For Internal Combustion Engines And Modular Diaphragm Elements For Said Silencer,” describes an essentially a cylindrical container with a series of cup-shaped catalytic converter elements arranged therein. The elements are each relatively thin, due to the cup-like shape of each element, and thus do not present a significant cross sectional area to the exhaust gases passing therethrough. Thus, a great many such elements are required, unlike the present catalytic converter and resonator combination.
U.S. Pat. No. 5,388,408 issued on Feb. 14, 1995 to Phillip G. Lawrence, titled “Exhaust System For Internal Combustion Engines,” describes a dual muffler system, in which the mufflers are teed from a single exhaust line upstream, which is in turn fed by one or more catalytic converters. The mufflers of the Lawrence system are essentially straight through devices having a series of pipes therein of different lengths. While the Lawrence system discloses dual mufflers, their connection to a single point upstream is unlike the dual exhaust embodiment of the present invention. Moreover, no V-shaped vanes are provided by Lawrence in combination with his plurality of different length tubes, nor does he provide one or more catalytic converter elements contained within the same housing as the muffler and resonator device, as is done with the present invention.
U.S. Pat. No. 5,398,504 issued on Mar. 21, 1995 to Tomotaka Hirota et al., titled “Layout Structure Of Catalytic Converters,” describes a system in which first and second converters are installed immediately adjacent the respective cylinder banks of a V-configuration engine. A separate third, main converter is provided beneath the engine. Each of the converters is contained in a separate housing or shell, unlike the combined catalytic converter and resonator of the present invention. Moreover, Hirota et al. do not disclose any form of exhaust silencing or noise attenuating means in their system, as is provided by the present catalytic converter and resonator combination.
U.S. Pat. No. 5,426,269 issued on Jun. 20, 1995 to Wayne M. Wagner et al., titled “Muffler With Catalytic Converter Arrangement; And Method,” describes a series of embodiments of a muffler having a conventional catalytic converter element axially disposed therein. The path of the exhaust gas flow may take any of a few different routes, depending upon the specific embodiment of the Wagner et al. device. In at least one embodiment, the flow passes axially through the muffler, from one end to the other. In at least one other embodiment, flow doubles back through the muffler shell to exit radially from a port adjacent the axial inlet. None of the embodiments disclose a multiple path internal configuration corresponding to that of the present device.
U.S. Pat. No. 5,477,014 issued on Dec. 19, 1995 to Stephen R. Dunne et al., titled “Muffler Device For Internal Combustion Engines,” describes an otherwise conventional muffler, but having an internal coating of zeolite material for protecting the underlying metal structure from corrosion. The Dunne et al. coating does nothing to catalyze exhaust emissions, but is solely directed to the protection of the metal structure of the muffler. Moreover, the Dunne et al. muffler is conventional, as noted above. Among other conventional features, it includes relatively small diameter internal passages, which have diameters smaller than those of the inlet and outlet pipes. This results in excessive flow restriction, which is avoided in at least one of the embodiments of the present exhaust system configuration with its relatively large diameter internal passages.
U.S. Pat. No. 5,521,339 issued on May 28, 1996 to Michael S. Despain et al., titled “Catalyst Muffler System,” describes a relatively small muffler unit intended for use on a two stroke cycle type engine, e.g., chainsaw, lawnmower, etc. The Despain et al. muffler passes the exhaust gases back over the catalytic converter element therein, after passing through the catalyst element. No multiple paths for exhaust gases are provided by the Despain et al. muffler, whereas the present system includes such passages in each of its various embodiments.
U.S. Pat. No. 5,650,599 issued on Jul. 22, 1997 to Peter E. Madden et al., titled “Noise Cancellation Method And Apparatus,” describes a device employing electronic noise canceling means. The device is primarily directed to use with a reaction type engine, e.g., a turbojet, rather than to the exhaust of a reciprocating engine or the like. The exhaust is divided into a series of separate ducts, with each duct having its own electronic noise canceling system or apparatus therein. No acoustic muffling or resonating means is disclosed by Madden et al., nor is any catalytic or other conversion of exhaust products disclosed by Madden et al.
U.S. Pat. No. 5,881,554 issued on Mar. 16, 1999 to James Michael Novak et al., titled “Integrated Manifold, Muffler, And Catalyst Device,” describes a relatively large and bulky assembly having a series of individual exhaust tubes within a larger manifold housing. The tubes lead to a catalytic converter element, with the internal manifold volume also communicating with the catalytic element. The tubes are perforated to allow gas flow to pass therefrom to the internal volume of the manifold, whereby the assembly acts as a resonator. However, while Novak et al. state that their device also serves as a muffler, no muffler elements are disclosed within the device. In contrast, the present system provides multiple flow paths as a muffler and resonator.
U.S. Pat. No. 5,992,560 issued on Nov. 30, 1999 to Hirotake Matsuoka et al., titled “Muffler For Internal Combustion Engine,” describes a straight through flow configuration having circumferentially surrounding acoustic absorbent material. The acoustic absorbent material is preferably glass fiber, which Matsuoka et al. describe as being susceptible to melting and forming small beads, which then pass through the perforations in the inner pipe to be blown from the exhaust system. Matsuoka et al. provide a “scattering prevention member” comprising a fine mesh wire screen surrounding the inner pipe, in order to retain any fine glass beads which may be formed, within their intended area. Matsuoka et al. do not disclose any multiple tube construction, multiple flow paths, catalytic converter elements, or other features of the present invention.
U.S. Pat. No. 6,089,347 issued on Jul. 18, 2000 to Ray T. Flugger, titled “Muffler With Partition Array,” describes a series of embodiments each having a number of angled deflector plates installed therein. Some of the embodiments include a series of V-shaped deflectors therein. However, none of the embodiments of the Flugger muffler configurations include any form of multiple pipes providing multiple flow paths, double wall construction, catalytic converter elements, or other features of the present exhaust system invention.
U.S. Pat. No. 6,109,026 issued on Aug. 29, 2000 to Egon Karlsson et al., titled “Muffler With Catalytic Converter,” describes a small canister type muffler for use with relatively small two stroke cycle type engines. The Karlsson et al. muffler has a configuration more closely resembling that of the Nagai et al. '467 and Despain et al. '339 U.S. Patents, than the present exhaust system invention. The points of difference raised in the discussion of the Nagai et al. and Despain et al. mufflers, are seen to apply here as well.
U.S. Pat. No. 6,394,225 issued on May 28, 2002 to Kazuhiro Yasuda, titled “Muffler Structure,” describes a muffler having a series of tubes installed within an outer shell. The tubes are held in place by internal baffles, which cause the gases to flow back and forth through the various tubes. However, Yasuda does not include any form of V-shaped baffles or guides within his muffler nor does he provide any form of catalytic converter element, removable end component, or other features of the present exhaust system invention.
Japanese Patent Publication No. 55-43262 published on Mar. 27, 1980 illustrates an exhaust gas purifier in which the catalytic converter unit includes a baffle within its inlet end to preclude interference between exhaust gases alternatingly entering the converter from the no. 1 and no. 4 cylinders, and the no. 2 and no. 3 cylinders. No muffler, resonator, or other sound attenuating means is apparent, as is provided in the present catalytic converter and resonator combination invention.
Japanese Patent Publication No. 57-41414 published on Mar. 8, 1982 illustrates a method of manufacturing a catalytic converter equipped with a muffler. The assembly includes a forward muffler with a catalytic converter welded thereto and downstream thereof, with a rear muffler welded to the downstream end of the catalytic converter. The present catalytic converter and resonator combination utilizes a single, monolithic shell enclosing both the catalytic converter and resonator components, with no welding of separate components being required to form the housing or shell for the device. A “protector 37” (per the English abstract), apparently comprising an outer shell spaced apart from the inner housing containing the catalytic converter, is welded over the remainder of the assembly, unlike the present catalytic converter and resonator combination with its single shell or housing. No disclosure is apparent regarding any provision for a straight through, free flow resonator or removable end component, as provided by the present invention.
Japanese Patent Publication No. 62-291,413 published on Dec. 18, 1987 to Michio Hayashi describes (according to the drawings and English abstract) a muffler configuration having a series of longitudinally disposed tubes therein, with the tubes held in place by a pair of baffles or bulkheads. Hayashi stiffens the bulkheads by forming them of two sheets of material with a fill of sound deadening material, in order to preclude vibration at certain frequencies. However, Hayashi does not provide any V-shaped guides or the like, nor does he provide a double wall shell extending for the entire length of the device, catalytic converter element(s), removable end component, or other features of the present exhaust system invention.
Japanese Patent Publication No. 64-12,017 published on Jan. 17, 1989 to Yoji Nagai describes (according to the drawings and English abstract) a catalytic converter construction wherein the converter is formed of a corrugated plate, with the plate surfaces being coated with the catalytic material. The corrugated plate is then rolled to form a multitude of channels, through which the exhaust gases pass and are catalytically reacted. Such a catalytic converter construction is also disclosed in the '859 U.S. Patent to Borla, discussed further above. While the present exhaust system invention may make use of such a catalytic converter construction, the '017 Japanese Patent Publication does not disclose the use of a double wall shell, removable end components, a catalytic converter in combination with other exhaust components, nor the specific internal construction of the present exhaust system invention.
Japanese Patent Publication No. 2-169,812 published on Jun. 29, 1990 to Yuichi Ito et al. describes (according to the drawings and English abstract) a muffler or the like wherein the outer shell is coated with a resin for rust and damage protection. Dual end caps are shown, but the outer outlet end cap and its attached exhaust pipe are not attached to the outlet tube of the device, which is held in place within the end of the exhaust pipe by the inner outlet end cap. This construction is quite different from that of any of the embodiments of the present invention. Moreover, while the '812 Japanese Patent Publication shows a series of internal tubes providing a sinusoidal flow path, there is no lateral gas flow between the tubes; all gases must flow from one end to the other sequentially, unlike the flow through the various embodiments of the present exhaust system invention. Such lateral flow and/or parallel flow paths are essential in a resonator type device, in order to separate and cancel various sound frequencies of the gases passing through the device. It is also noted that there is no provision for any form of V-shaped vanes or guides within the exhaust device of the '812 Japanese Patent Publication, whereas such internal vanes are a part of many of the embodiments of the present invention. Finally, the '812 Japanese Patent Publication does not appear to disclose any form of emissions treatment, such as the catalytic converter elements which are a part of most of the embodiments of the present invention.
European Patent Publication No. 475,398 published on Mar. 18, 1992 to Suzuki Kabushiki Kaisha, titled “Muffler Assembly For Engine,” describes a device having double wall construction with a series of three concentric internal pipes. None of the pipes communicate directly with one another, and the inlet end of the outlet pipe is capped. All gas flow into and from the pipes is through peripheral holes formed in the pipes. While the '398 European Patent Publication discloses a double wall construction, no insulation or other material is placed between the two walls. Also, there is no disclosure of any form of catalytic converter element(s) within the exhaust device of the '398 European Patent Publication.
Finally, Japanese Patent Publication No. 6-257,421 published on Sep. 13, 1994 to Kohei Tomita describes (according to the drawings and English abstract) an exhaust device having a configuration very similar to that of the '413 Japanese Patent Publication, discussed further above. As in the case of the '413 Japanese Patent Publication, the '421 Japanese Patent Publication does not disclose any V-shaped guides or the like, nor does it disclose a double wall shell extending for the entire length of the device, catalytic converter element(s), removable end component, or other features of the present exhaust system invention.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus exhaust sound and emission control systems solving the aforementioned problems are desired.